I have some collections that are in a password-protected section of a site. Is there anyway to exclude those collections from a site search, or only show them if they've already entered the password?

Other than using unique fields for those collections that are not listed in 'Searchable fields' (which would cause other problems) I can't see a solution in the docs.

I could also specify which collections to show results from, but then it would exclude pages that are not part of a collection.

Anyone have any pointers?